Benzodiazepines (BZDs) are extremely effective anxiolytics, and are among the most widely prescribed psychoactive drugs in current therapeutic use. BZDs, however, also exhibit undesirable side effects including sedative and myorelaxant activity.
Scutellaria baicalensis Georgi (commonly known as Huang Qin in Chinese and Ougon in Japanese) is one of the most important medicinal herbs in traditional Chinese medicine. It possesses anti-bacterial activity, sedative effects and finds application in the treatment of a range of conditions including diarrhea (Kubo, M., et al, Planta Medica 43:194–201, 1981) and hepatitis (Kimuya, Y., et al., Chem Pharm Bull 29: 2610–2617, 1981). Several individual compounds, including wogonin, baicalin, baicalein, scutellarein and skullcapflavone, have been extracted from this medicinal herb and tested for affinity to the benzodiazepine site (BZD-S) of the GABAA receptor to identify strongly binding ligands suitable for further study. The reports regarding the binding capacity of Scutellaria baicalensis Georgi extracts have been contradictory (Hui, K M, et al., Planta Med 56 91–93, 2000).